STEALTHMARK · HEAD TO HEAD

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Claude Opus 5.5 vs GPT 6.1 Sol

Claude Opus 5.5 scores 2.7 points higher overall (66.0 vs 63.3). Claude Opus 5.5 leads General Intelligence; GPT 6.1 Sol leads Visual Intelligence. Claude Opus 5.5 scores higher on Newton's Mirror, with its largest category advantage in reflections.

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Overall StealthMark

66.0/100
63.3/100

General Intelligence

55.3/100
47.6/100

Visual Intelligence

74.5/100
75.1/100

Newton's Mirror

Same prompt

Physics, perspective and recursive reflections, tested together. Explore the test ↗

Claude Opus 5.552.5/100

Claude Opus 5.5: Newton's Mirror SVG benchmark
Researcher observations

Open lateral sightlines, first reflected silhouettes and near-field planar panel placement are convincing. Missing outer chains, truncated repetitions and absent nested spherical room and emitter imagery remain the main weaknesses.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

GPT 6.1 Sol43.9/100

GPT 6.1 Sol: Newton's Mirror SVG benchmark
Researcher observations

Recognizable first sphere images and several central planar lights provide limited geometric agreement. Missing outer chains, truncated panel sequences and simplified interiors across the main, side and floor spheres leave most of the recursive reflection structure unsupported.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

Compare category scores
CategoryClaude Opus 5.5GPT 6.1 Sol
State at 600 ms25.0/2525.0/25
Camera and placement15.0/1515.0/15
Reflections46.5/12029.0/120
Materials and scale8.0/1010.0/10
Floor-damage reward0.0/100.0/10

Selfie

Different prompts

Claude Opus 5.578.3/100

Claude Opus 5.5: Selfie SVG benchmark
Researcher observations

The centered coral squid has a friendly, restrained expression and a balanced radial silhouette within a cream arch. Smooth curves and soft shading give it an appealing matte finish. The mantle is more elongated than compact, the upper arms are visually ambiguous, and the two hanging tentacles read somewhat like legs. Clean execution supports a strong stylized illustration.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

GPT 6.1 Sol76.5/100

GPT 6.1 Sol: Selfie SVG benchmark
Researcher observations

Six outward-facing heads and evenly arranged loops make the pale interlocking knot immediately readable. Uniform widths, angular inner bends and fine scales preserve its ornamental geometry. The bodies feel more like textured tubes than living muscle: shading is subdued, crossing contact shadows are weak, and visible curved seams interrupt surface continuity. Small heads have readable eyes and jaws but limited anatomical depth.

Prompt withheld

This prompt is held back to prevent benchmaxxing.

Compare category scores
CategoryClaude Opus 5.5GPT 6.1 Sol
Prompt & likeness8.0/108.5/10
Anatomy & construction7.5/107.5/10
Space & placement8.0/108.0/10
Light & reflections7.5/106.5/10
Purposeful detail7.5/107.0/10
Artistry & character8.0/108.0/10
Materials & effects7.5/106.5/10
Visual integrity8.5/108.0/10

Beach

Same prompt

Claude Opus 5.578.0/100

Claude Opus 5.5: Beach SVG benchmark
Researcher observations

A lively, well-composed beach illustration with rich sunset colors, recognizable animals and appealing accessories. The sun reflection establishes a strong central focus. Clean silhouettes and small details reward inspection, though simplified animal construction, uneven contact shadows and mostly flat materials limit depth and realism.

Exact prompt

Create an SVG of a amazing beach scene. Sunset, animals, fun, birds, reflections Make it a masterpiece, no tools allowed

GPT 6.1 Sol77.0/100

GPT 6.1 Sol: Beach SVG benchmark
Researcher observations

A cohesive sunset palette, sweeping shoreline and framing palm create an appealing beach illustration. Animals, birds, play and a prominent sun reflection fulfill the brief. Connected but schematic figures and simplified dolphin anatomy limit construction; stepped reflections and mostly flat surfaces limit lighting and material depth. Small beach accessories remain readable and edges are clean.

Exact prompt

Create an SVG of a amazing beach scene. Sunset, animals, fun, birds, reflections Make it a masterpiece, no tools allowed

Compare category scores
CategoryClaude Opus 5.5GPT 6.1 Sol
Prompt & likeness8.5/108.5/10
Anatomy & construction7.5/107.0/10
Space & placement7.0/107.5/10
Light & reflections8.0/107.5/10
Purposeful detail8.0/107.5/10
Artistry & character8.0/108.0/10
Materials & effects6.5/107.0/10
Visual integrity8.5/108.5/10

Mona Lisa

Same prompt

Claude Opus 5.564.8/100

Claude Opus 5.5: Mona Lisa SVG benchmark
Researcher observations

The portrait preserves the recognizable composition, dark veil, folded hands and distant landscape. Replication is limited by the elongated face and neck, conspicuous eyes and simplified smile. Hands remain connected but their rounded fingers and wrists lack convincing anatomy. Restrained colors create cohesion; shallow modeling and pervasive mottling weaken volume and painterly subtlety.

Exact prompt

Replicate mona-lisa as SVG Make it a masterpiece, no tools allowed

GPT 6.1 Sol64.8/100

GPT 6.1 Sol: Mona Lisa SVG benchmark
Researcher observations

The recognizable pose, dark clothing and misty landscape form a coherent portrait. Soft facial shading creates volume, but the broad face, outlined eyes and simplified smile limit likeness. Overlapping hands have flattened fingers and ambiguous separation. Angular landscape shapes and sparse fabric detail keep the execution competent rather than masterful.

Exact prompt

Replicate mona-lisa as SVG Make it a masterpiece, no tools allowed

Compare category scores
CategoryClaude Opus 5.5GPT 6.1 Sol
Prompt & likeness7.0/107.0/10
Anatomy & construction6.0/105.5/10
Space & placement6.5/107.0/10
Light & reflections6.0/107.0/10
Purposeful detail6.5/105.5/10
Artistry & character6.5/106.5/10
Materials & effects6.5/106.0/10
Visual integrity7.0/107.5/10

Raccoon

Same prompt

Claude Opus 5.575.0/100

Claude Opus 5.5: Raccoon SVG benchmark
Researcher observations

The masked raccoon clearly rides the dog's back, and the dog's forward paw reaches the steering grip. Expressive faces, vivid colors and sweeping wakes create an appealing illustration. Connected limbs remain schematic, as does the small steering assembly. The broad hull and flat foam weaken water contact; the glowing sun lacks a corresponding reflection or convincing cast shadows.

Exact prompt

Generate an SVG: A raccoon sits on a dog's back while the dog steers a jet ski Make it a masterpiece, no tools allowed

GPT 6.1 Sol78.5/100

GPT 6.1 Sol: Raccoon SVG benchmark
Researcher observations

The masked raccoon rides the dog's back, and the dog's forepaw meets a handlebar connected to the deck. Expressive faces, a striped tail and sweeping wake create an appealing composition. Overlapping bodies compress the seating and rear-leg anatomy; hull depth and sunset illumination remain schematic.

Exact prompt

Generate an SVG: A raccoon sits on a dog's back while the dog steers a jet ski Make it a masterpiece, no tools allowed

Compare category scores
CategoryClaude Opus 5.5GPT 6.1 Sol
Prompt & likeness8.5/108.5/10
Anatomy & construction7.0/107.5/10
Space & placement7.5/107.5/10
Light & reflections6.0/106.5/10
Purposeful detail7.5/108.0/10
Artistry & character8.0/108.5/10
Materials & effects7.0/107.5/10
Visual integrity8.0/108.5/10

Pelican

Benchmax control

Outside General and Visual Intelligence.

Claude Opus 5.572.5/100

Claude Opus 5.5: Pelican SVG benchmark
Researcher observations

The recognizable pelican, orderly bicycle wheels and harmonious sunset create an appealing illustration. Both legs connect to the body and reach pedals; no clear detached or inverted parts appear. Steering contact and seating support are less convincing, while the drivetrain remains schematic. Crisp outlines give a clean finish, but limited shading and flat surfaces leave the scene with modest depth.

Exact prompt

Generate an SVG of a pelican riding a bicycle Make it a masterpiece, no tools allowed

GPT 6.1 Sol79.0/100

GPT 6.1 Sol: Pelican SVG benchmark
Researcher observations

A clearly recognizable pelican rides a well-composed bicycle through a warm coastal scene. The expressive bill, restrained palette and carefully drawn wheels give the illustration character. Leg-to-pedal connections are less convincing, especially the obscured far foot. Lighting provides gentle volume but little directional shadow. The small subtitle is clipped at the lower border.

Exact prompt

Generate an SVG of a pelican riding a bicycle Make it a masterpiece, no tools allowed

Compare category scores
CategoryClaude Opus 5.5GPT 6.1 Sol
Prompt & likeness8.5/109.0/10
Anatomy & construction6.5/107.0/10
Space & placement7.0/108.0/10
Light & reflections6.0/107.0/10
Purposeful detail7.5/108.0/10
Artistry & character7.5/108.5/10
Materials & effects6.0/107.5/10
Visual integrity8.5/108.0/10